?A software error may cause an unwanted pressure pulsation in the transmission during a "Remote Engine Start."
full bulletin at NHTSA ↗2021 BMW M340i powertrain problems
moderate 3 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Complaints
3
Recalls
0
Avg fix
$2,500
When does it fail?
Of the 3 powertrain complaints filed for the 2021 BMW M340i, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
No new NHTSA powertrain complaint has been filed on this vehicle in over 3 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
BMW AG has issued an Emissions Recall (effective March 17, 2023) on a certain Model Year 2021 - 2023 BMW vehicles that were produced between June 16, 2020, and December 13, 2022. Due to a software failure, there is the possibility that the transmission does not go into "sleep mode" if the car is turned off.
full bulletin at NHTSA ↗BMW AG has issued a Delivery Stop: Due to a software failure, there is the possibility that the transmission does not go into "sleep mode" if the car is turned off.
full bulletin at NHTSA ↗There is a howling or whistling noise from under the vehicle at 30 -37 mph (50 -60 km/h) when driving after a cold start, when the outside temperature is 32 F (0 C) or lower. The noise goes away as the vehicle/driveline reaches operating temperature.
full bulletin at NHTSA ↗SERVICE ACTION: PROGRAM OR REPLACE DUAL STORAGE SYSTEM BATTERY: A software error intermittently causes a continuous resetting of the microcontroller in the power management system. This causes the red Check Control Message (CCM) "Replace Battery" to be illuminated.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 3 most recent
The contact owns a 2021 BMW M340I. The contact stated while driving various speeds, the vehicle independently shifted from reverse(R) to drive(D) to park(P). The contact stated that while driving approximately 10 MPH and attempting to stop the vehicle, the brake pedal was depressed and went to the floorboard. The contact stated that the brake failed to operate as designed. The vehicle was towed…
Here’s a strong version that sounds frustrated but still credible and harder to dismiss: I’ve owned many vehicles over the years, and this BMW has been, without question, the most problematic car I’ve ever had. The list of issues has been absurd for a vehicle in this price range and from a brand that markets itself as a premium luxury manufacturer. The sunroof failed, I’ve had multiple tire…
While driving through an intersection and making a left turn, a failure of the engine water pump pulley caused the pulley to break apart. This led to damage to the coolant line and tensioner, sudden coolant loss, and the serpentine belt slipping off. The failure occurred mid-turn, causing the vehicle to skid and momentarily lose steering control. I narrowly avoided a collision with an oncoming…
Had powertrain trouble with your 2021 BMW M340i?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 BMW M340i?
It's a documented issue but not catastrophic. 3 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Based on the 3 complaints filed, powertrain issues most often appear around 4,000 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/BMW/M340i.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.